US-South Korea Alliance Frays as Intel Sharing Stalls

South Korea’s top envoy to Washington, Kang Kyung-wha, told lawmakers Monday that Seoul’s communication with the White House is limited—and she isn’t hiding her irritation. “There are limitations in our communication with the White House,” she said. “I find it somewhat frustrating.” Her blunt admission of an “issue” with Washington’s sharing of covert data lays bare how far a decades-old security partnership has slipped, even as North Korea’s nuclear arsenal grows.

An Alliance Under Pressure

The friction isn’t new, and it isn’t confined to one dispute. Reports earlier in 2026 said a South Korean official had disclosed U.S. intelligence about a secret North Korean nuclear facility. President Lee Jae Myung rejected the allegations as “absurd.” That same month, reports that a prominent South Korean politician’s visa was held up forced him to cancel a U.S. trip. President Donald Trump had also scaled back military drills with South Korea. In June, local media reported that Washington excluded South Korea’s spy agency, at its request, from a trilateral U.S.-Japan meeting on North Korea.

Trade and investment quarrels have fed the security strain. Washington and Seoul have faced months of friction over U.S. accusations that South Korea delayed its investment deal and discriminated against American-listed e-commerce company Coupang. Last month, Lee publicly questioned Washington’s characterization of Seoul’s participation in a liquefied natural gas project in Alaska, saying cooperation depended on the deal being financially viable. Trump’s complaints that South Korea hadn’t done more to help with Iran, along with U.S. promises to assist Seoul with nuclear-powered submarines that remain unfulfilled, soured things further.

What’s at Stake on the Peninsula

The timing is hard. North Korea has increased missile tests, can produce as many as 20 nuclear weapons a year, and has declared the South its “principal enemy.” Washington provides Seoul with direct military deterrence against that threat. There’s no sign the United States would withdraw any of its 28,000 troops stationed on the Korean peninsula ahead of schedule. But reduced intelligence cooperation makes it harder for Seoul to respond to Pyongyang’s growing arsenal.

Victor Cha, Korea chair at the Center for Strategic and International Studies, put the danger plainly. “The most damaging aspect of the friction over intelligence restrictions is it conveys the U.S. does not have trust in Korea as an ally,” he said. “It’s serious because it hits at the heart of the military alliance.” Jenny Town, a senior fellow at the Stimson Center, said South Korea’s problems were “more pronounced in scope and severity” than those of other U.S. allies, painting “a picture of an alliance that’s highly strained and losing trust.”

Official Responses and Political Calculations

The U.S. State Department declined to comment, and the White House didn’t respond to a request for comment. An official at South Korea’s presidential office said the government was working to strengthen trust with the United States and stressed that the alliance was the cornerstone of Seoul’s foreign and security policy. South Korea’s National Intelligence Service didn’t respond to calls for comment.

Lee met Trump briefly in New York last month on the sidelines of the United Nations General Assembly and sought help restarting dialogue with North Korea. “President Trump kindly reminded me of our plan to play golf,” Lee said after the 30-minute meeting. South Korea later set up a task force to prepare for a golf outing between the two men ahead of the Group of 20 summit in December, Yonhap News reported. Trump, meanwhile, has floated restarting talks with Kim Jong Un.

Kim Jung, a professor at the University of North Korean Studies in Seoul, noted that during Trump’s first term, South Korea’s national security adviser and intelligence chief were key to arranging meetings between Trump and North Korea’s leader. “This government’s ability to manage the situation is now being put to the test,” he said. That week, Lee told his cabinet that South Korea, as a sovereign nation, should “avoid a submissive or overly deferential approach in relations with other countries.” The report described his approach as “pragmatic diplomacy,” seeking warmer relations with China while keeping close ties with the United States. His spy chief and unification minister were seen as part of a faction favoring better relations with Beijing, a stance some analysts said had gone down badly among China hawks in Washington.

Domestic politics are sharpening the dispute on both sides. “Trump is pushing the Alaska LNG project as he looks to bolster Republicans ahead of the midterms, while Lee has incentives to push back forcefully as he faces weak approval ratings,” said Bloomberg Economics’ Adam Farrar. Former Vice President Kamala Harris criticized Trump in Seoul on Wednesday for undermining the alliance by cutting drills and using tariffs to threaten partner nations. “Changing circumstances require a renewal of our commitment to South Korea,” she said. “America must be strategic in the use of our economic power, not reckless or spiteful.”

Why This Matters:

An alliance isn’t just a treaty. It runs on trust, shared intelligence and predictable cooperation, and each is now under strain. For roughly 28,000 U.S. troops on the peninsula and South Koreans living within range of a North Korean arsenal growing by as many as 20 weapons a year, degraded intelligence sharing carries real risk. Trade penalties threatened amid the disputes add economic uncertainty on top of security anxiety. The episode also shows how transactional demands, from tariffs to investment deals, can bleed into collective defense, where shared institutions and steady multilateral coordination have traditionally provided stability. Whether Washington and Seoul can rebuild trust before the December Group of 20 summit may shape how both capitals approach Pyongyang.